Getting data from another page

Hello.
I think this should be a real simple one but for some reason I can't seam to manage it.
I have a slogan that runs through all my site.
Currently I have a custom "Slogan" field in the CMS for every page type. And I retype the slogan into there for every page.
What I want to do is to get the "Slogan" field from the top most parent HomePage page type.
I might have two HomePage page types fathering different children with different slogans and so I would like the page that is asking for the slogan to pick it up from it's first parent HomePage page type.

Brilliant!
I knew there was an almost blindingly simple way to do this.
Thanks.

But say I want the template to grab the "Slogan" from it's topmost parent.
Just using $Parent.Slogan will only go one level up.
How would I get to the root HomePage dynamically without giving it a hardcoded name using the: